Page: 44Service Guide ML520/521Chapter 2 Principles of OperationPrinthead Gap InformationThree items factor into printhead gap information.1. Printhead Gap AdjustmentThis is a SERVICE ADJUSTMENT made by a technician.It is covered in Section 3.3 of this Service Handbook.The Adjustment measures 0.014, +/- 0.001 inches (0.35, +/- 0.03 mm).2. Printhead Gap AdjustThis is a MENU ITEM in the SET-UP Group.It fine tunes the automatic setting of the printhead gap.The settings are 0, 1, and -1.0 is the factory default.Use 1 todarken print (if output isconsistently light).Use - 1 tolighten print (if output isconsistently dark).3. Gap ControlThis is a MENU ITEM ineach [Paper Feed] Group.The Groups are REAR FEED, BOTTOM FEED, and TOP FEED.Gap Control determines how the printhead gap is set.The settings are listed below.Auto Gap, Semi Auto Gap, 1, 2, 3, 4, 5, 6, 7, 8, 9An explanation of each setting follows.Auto GapThis is the factory default.Automatically determines paper thickness of the first page.During single-sheet feed, each pages thickness is checkedwhile a job is printing.
